Back to EveryPatent.com
| United States Patent |
5,219,915
|
|
McKee
, et al.
|
June 15, 1993
|
Glass fiber-reinforced thermoplastic molding materials based on
polyesters and graft polymers
Abstract
Thermoplastic molding materials based on a mixture of polybutylene
terephthalate and polyethylene terephthalate (a.sub.1), graft polymers
having acrylate rubbers as the grafting base (a.sub.2), copolymers of
vinylaromatic monomers and acrylonitrile or methacrylonitrile (a.sub.3)
and glass fibers (B) have a balanced property spectrum.
| Inventors:
|
McKee; Graham E. (Weinheim, DE);
Knoll; Manfred (Wachenheim, DE);
Kolm; Peter (Neustadt, DE);
Lausberg; Dietrich (Ludwigshafen, DE)
|
| Assignee:
|
BASF Aktiengesellschaft (Ludwigshafen, DE)
|
| Appl. No.:
|
762261 |
| Filed:
|
September 20, 1991 |
Foreign Application Priority Data
| Current U.S. Class: |
524/504; 524/494; 525/78; 525/83; 525/85 |
| Intern'l Class: |
C08L 051/04 |
| Field of Search: |
524/494,504
525/78,83,85
|
References Cited
U.S. Patent Documents
| 4145331 | Mar., 1979 | Sterzel et al. | 524/504.
|
| 4397986 | Aug., 1983 | Hornbaker | 525/64.
|
| 4739010 | Apr., 1988 | McKee et al. | 525/64.
|
| 4939201 | Jul., 1990 | Seiler et al. | 524/504.
|
| Foreign Patent Documents |
| 0297365 | Jan., 1989 | EP.
| |
| 0310956 | Apr., 1989 | EP.
| |
| 2255654 | Apr., 1976 | DE.
| |
| 2758497 | Apr., 1979 | DE.
| |
| 3733839 | Apr., 1989 | DE.
| |
Primary Examiner: Michl; Paul R.
Assistant Examiner: Cain; Edward
Attorney, Agent or Firm: Oblon, Spivak, McClelland, Maier & Neustadt
Parent Case Text
This application is a continuation of application Ser. No. 07/497,671,
filed on Mar. 32, 1990, now abandoned.
Claims
We claim:
1. A thermoplastic molding material consistently essentially of,
A) from 45 to 90% by weight of a mixture of
a.sub.1) from 50 to 80% by weight of a mixture of
a.sub.11) from 60 to 99% by weight, based on a.sub.11 +a.sub.12 ), of
polybutylene terephthalate and
a.sub.12) from 1 to 90% by weight, based on a.sub.11 +a.sub.12), of
polyethylene terephthalate,
a.sub.2) from 10 to 25% by weight of a graft polymer composed of
a.sub.21) from 50 to 90% by weight of a grafting base of an elastomeric
polymer based on
a.sub.211) from 75 to 99.9% by weight of a C.sub.2 -C.sub.10 -alkyl
acrylate and
a.sub.212) from 0.1 to 5% by weight of a polyfunctional monomer having two
or more olefinic, nonconjugated double bonds and
a.sub.213) from 0 to 24.9% by weight of further copolymerizable monomers,
and
a.sub.22) from 10 to 50% by weight of a graft of
a.sub.221) from 50 to 90% by weight of styrene or substituted styrenes of
the formula I
##STR3##
where R is alkyl of 1 to 8 carbon atoms, hydrogen or halogen, R.sup.1 is
alkyl of 1 to 8 carbon atoms or halogen and n is 0, 1, 2 or 3, or a
mixture thereof, and
a.sub.222) from 10 to 49% by weight of acrylonitrile or methacrylonitrile
or a mixture thereof,
a.sub.3) from 10 to 25% by weight of a copolymer of
a.sub.31) from 50 to 90% by weight of styrene or substituted styrenes of
the formula I or a mixture thereof and
a.sub.32) from 10 to 49% by weight of acrylonitrile or methacrylonitrile or
a mixture thereof, and
B) from 5 to 50% by weight of glass fibers.
2. A thermoplastic molding material as claimed in claim 1, consisting
essentially of,
A) from 55 to 90% by weight of a mixture of
a.sub.1) from 50 to 80% by weight of a mixture of
a.sub.11) from 60 to 99% by weight, based on a.sub.11 +a.sub.12), of
polybutylene terephthalate and
a.sub.12) from 1 to 40% by weight, based on a.sub.11 +a.sub.12), of
polyethylene terephthalate,
a.sub.2) from 10 to 25% by weight of a graft polymer of
a.sub.21) from 50 to 90% by weight of a grafting base consisting of
a.sub.211) from 75 to 99.9% by weight of n-butyl acrylate and/or
2-ethylhexyl acrylate and
a.sub.212) from 0.1 to 5% by weight of a bifunctional monomer and
a.sub.213) from 0 to 24.9% by weight of buta-1,3-diene, styrene,
acrylonitrile, methacrylonitrile and/or C.sub.1 -C.sub.8 -methacrylates,
and
a.sub.22) from 10 to 50% by weight of a graft of
a.sub.211) from 50 to 90% by weight of styrene or .alpha.-methylstryene or
a mixture thereof and
a.sub.222) from 10 to 49% by weight of acrylonitrile or methacrylonitrile
or a mixture thereof,
a.sub.3) from 10 to 25% by weight of a copolymer of
a.sub.31) from 50 to 90% by weight of styrene or .alpha.-methylstyrene or a
mixture thereof and
a.sub.32) from 10 to 49% by weight of acrylonitrile or methacrylonitrile or
a mixture thereof, and
B) from 10 to 40% by weight of glass fibers.
3. A molding produced from a thermoplastic molding material as claimed in
claim 1.
4. A thermoplastic molding material as claimed in claim 1, wherein a.sub.11
is from 75 to 97% by weight, based on a.sub.11 +a.sub.12, and wherein
a.sub.12 is from 3 to 25% by weight, based on a.sub.11 +a.sub.12.
5. A thermoplastic molding material as claimed in claim 2, wherein a.sub.11
is from 75 to 97% by weight, based on a.sub.11 +a.sub.12, and wherein
a.sub.12 is from 3 to 25% by weight, based on a.sub.11 +a.sub.12.
Description
The present invention relates to thermoplastic molding materials
containing, as essential components,
A) from 45 to 90% by weight of a mixture of
a.sub.1) from 50 to 80% by weight of a mixture of
a.sub.11) from 60 to 99% by weight, based on a.sub.11 +a.sub.12), of
polybutylene terephthalate and
a.sub.12) from 1 to 40% by weight, based on a.sub.11 +a.sub.12), of
polyethylene terephthalate,
a.sub.2) from 10 to 25% by weight of a graft polymer composed of
a.sub.21) from 50 to 90% by weight of a grafting base of an elastomeric
polymer based on
a.sub.211) from 75 to 99.9% by weight of a C.sub.2 -C.sub.10 -alkyl
acrylate and
a.sub.212) from 0.1 to 5% by weight of polyfunctional monomer having two or
more olefinic, nonconjugated double bonds and
a.sub.213) from 0 to 24.9% by weight of further copolymerizable monomers,
and
a.sub.22) from 10 to 50% by weight of a graft of
a.sub.221) from 50 to 90% by weight of styrene or substituted styrenes of
the general formula I
##STR1##
where R is alkyl of 1 to 8 carbon atoms, hydrogen or halogen, R.sup.1 is
alkyl of 1 to 8 carbon atoms or halogen and n is 0, 1, 2 or 3, or a
mixture thereof, and
a.sub.222) from 10 to 49% by weight of acrylonitrile or methacrylonitrile
or a mixture thereof,
a.sub.3) from 10 to 25% by weight of a copolymer of
a.sub.31) from 50 to 90% by weight of styrene or substituted styrenes of
the general formula I or a mixture thereof and
a.sub.32) from 10 to 49% by weight of acrylonitrile or methacrylonitrile or
a mixture thereof, and
B) from 5 to 50% by weight of glass fibers.
The present invention furthermore relates to the use of such molding
materials for the production of moldings, and moldings which are
obtainable from the novel molding materials as essential components.
DE-B-27 58 497 describes thermoplastic molding materials based on
polyesters and modified styrene/acrylonitrile (SAN) copolymers, the
modifiers used being acrylates and/or .alpha.-methylstyrene. In the
Examples, ASA polymers are used as modified SAN polymers. If the modified
SAN polymers constitute the main component in these materials, they can
advantageously be used for the production of films. However, the
mechanical properties in general are not completely satisfactory, in
particular the impact strength and flexural strength. The stability of the
properties after prolonged storage at elevated temperatures is also
unsatisfactory.
DE-B 22 55 654 describes blends of polybutylene terephthalate and
polyethylene terephthalate; however, there is no mention of the graft
polymers and copolymers used according to the invention.
It is an object of the present invention to provide thermoplastic molding
materials which are based on polyesters and graft polymers and do not have
the disadvantages described above. In particular, satisfactory long-term
stability of the mechanical properties at elevated temperatures should
also be achieved.
We have found that this object is achieved, according to the invention, by
the thermoplastic molding materials defined at the outset.
The novel molding materials contain, as component A, from 45 to 90, in
particular from 55 to 90, particularly preferably from 60 to 85, % by
weight of a mixture of
a.sub.1) from 50 to 80% by weight of a mixture of
a.sub.11) from 60 to 99, preferably from 75 to 97, % by weight, based on
a.sub.11 +a.sub.12), of polybutylene terephthalate and
a.sub.12) from 1 to 40, preferably from 3 to 25, % by weight, based on
a.sub.11 +a.sub.12), of polyethylene terephthalate,
a.sub.2) from 10 to 25% by weight of a graft polymer and
a.sub.3) from 10 to 25% by weight of a styrene/(meth)acrylonitrile
copolymer.
The polyesters a.sub.11 and a.sub.12 contained in the novel molding
materials are known per se.
The polyesters can be prepared by reacting terephthalic acid, its esters or
other ester-forming derivatives with butane-1,4-diol or ethane-1,2-diol in
a conventional manner.
Up to 20 mol % of the terephthalic acid may be replaced with other
dicarboxylic acids. Naphthalenedicarboxylic acids, isophthalic acid,
adipic acid, azelaic acid, sebacic acid, dodecanedioic acid and
cyclohexanedicarboxylic acids, mixtures of these carboxylic acids and
ester-forming derivatives thereof may be mentioned here merely by way of
example.
Up to 20 mol % of the dihydroxy compounds butane1,4-diol or ethane-1,2-diol
may furthermore be replaced with other dihydroxy compounds, e.g.
butene-1,4-diol, hexane-1,6-diol, hexane-1,4-diol, cyclohexane-1,4-diol,
1,4-di-(hydroxymethyl)-cyclohexane, bisphenol A, neopentylglycol, mixtures
of these diols and ester-forming derivatives thereof.
The viscosity number of the polyesters a.sub.11 and a.sub.12, measured in a
0.5% strength by weight solution in a phenol/o-dichlorobenzene mixture
(weight ratio 1:1) at 25.degree. C., is in general 50-250, preferably
70-170, cm.sup.3 /g.
The amount of the polyesters a.sub.1) in component A from 50 to 70, % by
weight, based on the total weight of components
a.sub.1)+a.sub.2)+a.sub.3).
The graft polymer a.sub.2), which accounts for from 10 to 25, in particular
from 12 to 25, particularly preferably from 12 to 20, % by weight of
component A, is composed of
a.sub.21) from 50 to 90% by weight of a grafting base consisting of
a.sub.211) from 75 to 99.9% by weight of a C.sub.2 -C.sub.10 -alkyl
acrylate,
a.sub.212) from 0.1 to 5% by weight of a polyfunctional monomer having two
or more olefinic, nonconjugated double bonds, and
a.sub.213) from 0 to 24.9% by weight of further copolymerizable monomers,
and
a.sub.22) from 10 to 50% by weight of a graft of
a.sub.221) from 50 to 90% by weight of styrene or substituted styrenes of
the general formula I or a mixture thereof, and
a.sub.222) from 10 to 50% by weight of acrylonitrile or methacrylonitrile
or a mixture thereof.
Component a.sub.21) is an elastomer which has a glass transition
temperature of less than -20.degree. C., in particular less than
-30.degree. C.
For the preparation of the elastomer, esters of acrylic acid having 2 to
10, in particular 4 to 8, carbon atoms are used as main monomers
a.sub.211). Examples of particularly preferred monomers are iso- and
n-butyl acrylate and 2-ethylhexyl acrylate, of which the two
last-mentioned are particularly preferred.
In addition to these esters of acrylic acid, from 0.1 to 5, in particular
from 1 to 4, % by weight, based on the total weight of a.sub.211
+a.sub.212, of a polyfunctional monomer having two or more olefinic double
bonds are used. Of these, difunctional compounds, i.e. compounds having
two nonconjugated double bonds, are preferably used. Examples of these are
divinylbenzene, diallyl fumarate, diallyl phthalate, triallyl cyanurate,
triallyl isocyanurate, tricyclodecenyl acrylate and
dihydrodicyclopentadienyl acrylate, of which the two last-mentioned are
particularly preferred.
In addition to the monomers a.sub.211) and a.sub.212), up to 24.9,
preferably up to 20% by weight of further copolymerizable monomers,
preferably buta-1,3-diene, styrene, .alpha.-methylstyrene, acrylonitrile,
methacrylonitrile and C.sub.1 -C.sub.8 -alkyl esters of methacrylic acid
or mixtures of these monomers, may also be used in the synthesis of the
grafting base.
Processes for the preparation of the grafting base a.sub.21) are known per
se and are described in, for example, DE-B 1 260 135. Corresponding
products are also commercially available.
Preparation by emulsion polymerization has proven particularly advantageous
in some cases.
The amount of the grafting base a.sub.21) in the graft polymer a.sub.2) is
from 50 to 90, preferably from 55 to 85, in particular from 60 to 80, % by
weight, based on the total weight of a.sub.2).
A graft shell a.sub.22), which is obtainable by co-polymerization of
a.sub.221) from 50 to 90, preferably from 60 to 90, in particular from 65
to 80, % by weight of styrene or substituted styrenes of the general
formula I
##STR2##
where R is alkyl of 1 to 8 carbon atoms, hydrogen or halogen and R.sup.1
is alkyl of 1 to 8 carbon atoms or halogen, n is 0, 1, 2 or 3, and
a.sub.222) from 10 to 50, preferably from 10 to 40, in particular from 20
to 35, % by weight of acrylonitrile or methacrylonitrile or a mixture
thereof,
is grafted onto the grafting base a.sub.21).
Examples of substituted styrenes are .alpha.-methylstyrene,
p-methylstyrene, p-chlorostyrene and p-chloro-.alpha.-methylstyrene;
styrene and .degree. -methylstyrene are particularly preferred as monomers
a.sub.221.
The graft shell a.sub.22) can be prepared in one process step or in a
plurality of, for example two or three, process steps, the overall
composition remaining unaffected by this.
The graft shell is preferably prepared in emulsion, as described in, for
example, German Patent 1,260,135 and German Laid-Open Applications DOS
3,227,555, DOS 3,149,357 and DOS 3,414,118.
Depending on the conditions chosen, a certain amount of free copolymers of
the monomers a.sub.221) and a.sub.222) is formed during the graft
copolymerization.
The graft copolymer (a.sub.21 +a.sub.22) generally has a median particle
size of from 50 to 1,000 nm, in particular from 80 to 700 nm (d.sub.50
value based on weight). The conditions during the preparation of the
elastomer a.sub.21) and during grafting are therefore preferably chosen so
that particle sizes in this range result. Measures for this purpose are
known and are described in, for example, German Patent 1,260,135, German
Laid-Open Application DOS 2,826,925 and J. Appl. Polym. Sci. (1965),
2929-2938. The particle sizes of the latex of the elastomer can be
increased, for example, by agglomeration.
For the purposes of the present invention, the graft polymers a.sub.2
include the free, ungrafted homo- and copolymers formed in the graft
copolymerization for the preparation of component a.sub.22). A few
preferred graft polymers are listed below:
a.sub.2 /1: 60% by weight of grafting base a.sub.21) of
a.sub.211) 98% by weight of n-butyl acrylate and
a.sub.212) 2% by weight of dihydrodicyclopentadienyl acrylate and 40% by
weight of graft shell a.sub.22) of
a.sub.221) 75% by weight of styrene and
a.sub.222) 25% by weight of acrylonitrile
a.sub.2 /2: Grafting base as for a.sub.2 /1, with 5% by weight of a first
graft shell of styrene and 35% by weight of a second graft shell of
a.sub.221) 75% by weight of styrene and
a.sub.222) 25% by weight of acrylonitrile
a.sub.2 /3: Grafting base as for a.sub.2 /1, with 13% by weight of a first
graft shell of styrene and 27% by weight of a second graft shell of
styrene and acrylonitrile in a weight ratio of 75:25.
The novel molding materials contain, as component a.sub.3), from 10 to 25,
preferably from 12 to 20, % by weight of a copolymer of
a.sub.31) from 50 to 90, preferably from 55 to 90, in particular from 65 to
80, % by weight of styrene and/or substituted styrenes of the general
formula I and
a.sub.32) from 10 to 50, preferably from 10 to 45, in particular from 20 to
35, % by weight of acrylonitrile and/or methacrylonitrile.
The novel molding materials are distinguished by good strength, high impact
strength and a particularly good surface structure of the moldings
produced therefrom. Furthermore, the deformation properties and the heat
distortion resistance are particularly advantageous.
EXAMPLES
The following components were used:
a.sub.11) polybutylene terephthalate having a viscosity number of 108
cm.sup.3 /g, determined according to DIN 53,728,
Part 2 (Ultradur.RTM. B2550 from BASF AG)
a.sub.12) polyethylene terephthalate having a viscosity number of 75
cm.sup.3 /g (0.5% strength in 60:40 phenol/o-dichlorobenzene at 25.degree.
C.)
a.sub.2) Graft polymer of
______________________________________
58.8% by weight of n-butyl acrylate
1.2% by weight of dihydrodicyclo-
Grafting base
pentadienyl acrylate
30% by weight of styrene
Graft shell
10% by weight of acrylonitrile
______________________________________
Graft shell prepared by the process described in DE-A 24 44 584.
a.sub.3) Styrene/acrylonitrile copolymer (weight ratio 65: 35) having a
viscosity number of 80, measured in 0.5% strength solution in
dimethylformamide (DMF) at 25.degree. C.
B) Glass fibers
The compositions of both Examples also contained the following additives
(in each case in % by weight, based on the total weight of A)+B)):
1.5% by weight of carbon black
0.1% by weight of talc
0.8% by weight of pentaerythritol stearate
The compositions described in the Table were melted and the melts were
extruded. After extrusion, the test specimens required for the
determinations of the properties were produced by injection molding.
The results of the measurements are shown in the Table.
______________________________________
Example 2
Component Example 1 Comparison
______________________________________
a.sub.11 (% by weight)
48 56
a.sub.12 (% by weight)
8 --
a.sub.2 (% by weight)
12 12
a.sub.3 (% by weight)
12 12
B (% by weight) 20 20
Total energy W.sub.50 [Nm].sup.1
4.5 2.5
Surface gloss (DIN 67,530)
88 70
Surface quality Good Less good
Glass fibers
Glass fibers
not visible
visible
Minimum charging pressure for
380 400
injection molding a test box [bar]
Deformation of test box, measured
0.48 0.60
along the longitudinal side [mm]
Heat distortion resistance (.degree.C.)
186 170
Colorability Good Less good
______________________________________
.sup.1 Penetration test according to DIN 53,443 on 2 mm circular disks
The results in the Table show clearly that the novel materials are superior
in their property spectrum to the materials disclosed in DE-B 2 758 497.
Top